A novel multifunctional fluorescent capillary-based sensor for simultaneous monitoring of pH, O and CO.

A fluorescent capillary sensor for detecting the bioanalytically and biologically relevant analytes pH, O, and CO has been designed. The sensor is based on single capillary tube with 2 mm inner diameter, which is simultaneous doped with emissive O-sensitive indicator Ru(dpp)(PF6) (RuDP), pH-sensitive and CO-sensitive indicator 8-hydroxypyrene-1, 3,6-trisulfonic acid trisodium salt (HPTS). The multifunctional sensor can be excited at the same wavelength and realize multi-parameter optical monitoring at the different sensing position.

Fluorescein isothiocyanate-doped conjugated polymer nanoparticles for two-photon ratiometric fluorescent imaging of intracellular pH fluctuations.

Herein, we report a two-photon ratiometric fluorescent pH nanosensor based on conjugated polymer poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) nanoparticles loaded with pH-sensitive fluorescein isothiocyanate (FITC) for intracellular pH monitoring. The obtained nanosensor (FITC-PFO NPs) possesses high sensitivity, excellent stability, good reversibility, favorable two-photon excitability and low cytotoxicity. The ratiometric fluorescence of FITC and PFO (F/F) in FITC-PFO NPs solution shows an efficient pH-sensitive response over the pH range from 3 to 10 (pKa = 6.